1. Field of the Invention
The present invention relates to recording devices for digital data streams, and particularly to methods and systems for restricting distribution of copies recorded on such devices.
2. Description of the Related Art
Digital recording technology makes it possible to easily reproduce exact copies of digital data streams such as audiovisual material, including movies, television programs, and audio recordings. Compression technologies, such as specified by the Motion Pictures Expert Group (MPEG), reduce the requirements for data storage space so that it is possible to store such recordings on a hard disk, such as the hard disk in a personal computer (PC). Once content is captured on a hard disk, it is simple to make large numbers of copies on writable compact disks (CD's) or DVD disks, for example, or to distribute the content to others over network connections, such as over the Internet.
Such copying capability poses the threat that illegal copying can become widespread, causing significant economic losses to the owners of proprietary rights to the content. There is thus a need to protect recorded content from illicit reproduction and distribution, i.e., copyright infringement.